The present invention relates to an apparatus for feeding wires to varying predetermined lengths.
There are numerous machines used in the electrical harness making industry which require intermittent feeding of predetermined lengths of wire from an endless source such as a reel or barrel. U.S. Pat. No. 4,043,494 discloses an apparatus for feeding wire in such a manner by utilizing a single wire feed roll driven by a printed circuit motor which coacts with pivotal pressure rolls to drive wires therebetween. The apparatus of U.S. Pat. No. 4,043,494 is directed to achieving high constant levels of both acceleration and deceleration of the feed roll in order to reduce the time to feed a given length of wire and thus permit a higher operating speed of the harness making machinery. A wire clamp is provided which opens at the start of a feeding cycle and closes at the end of the cycle so that feeding is precisely controlled. The clamp and pivotal pressure rolls are mounted on side by side levers which are connected with side by side piston cylinders which move said levers such that each clamp bears on a wire while the respective pressure roll moves out of contact therewith and vice-versa.
In accordance with one aspect of the instant invention, individual fixed feed wheels on a common drive shaft coact with driven pivotal feed wheels which individually move vertically from a coaxial array toward respective fixed feed wheels to grip wires therebetween. Wire control is thus improved over the prior art insofar as driven feed wheels contact the wire being fed on both sides, as opposed to having a driven wheel or roller on one side and an idler on the other. Synchronous rotation is achieved by having a fixed gear on the drive shaft adjacent to each fixed wheel which is never entirely out of mesh with a pivotal gear mounted fixedly with respect to an adjacent pivotal feed wheel. The positive gripping thus achieved improves wire feed performance against a greater wire tension than is possible with a single driven wheel for each wire. The improved gripping achieved by having a driven pivotal wheel for each wire also obviates the need for a clamp, since the wire is positively stopped when coacting wheels stop rotating. In accordance with another aspect of the instant invention, each wire is fed closely between toothed portions of adjacent fixed gears where borne against by coacting fixed and pivotal feed wheels, whereby the fixed gears form part of a wire guide.
In accordance with yet another aspect of the present invention, bifurcated pivot arms carrying pivotal feed wheels at their ends are staggered to opposite sides of the coaxial array of pivotal feed wheels to allow more room for actuators and other linkage associated with the pivot arms, thereby taking best advantage of available space.
Another aspect of the invention is the utilization of a system of auxiliary fixed and pivotal feed wheels driven by spur gears off of the drive shaft and arranged to feed a second level of wires. The second level receives wires through wire guides which diverge vertically from wire guides feeding the first level, all guides having entries in a single plane, whereby a coplanar array of wires can be fed through two feed levels and return to a coplanar array through a similar set of converging guides on the opposite side of the feed wheels.
It is thus an object of the present invention to provide an improved wire feeding apparatus which may be used in conjunction with harness making equipment or mass terminating equipment. An object is to provide improved wire gripping during feed to effect precise control of lengths of wire being fed. An object is to take maximum advantage of space limitations so that a large number of wires may be fed.
The accomplishment of these and other objects will be apparent from the description of the preferred embodiment which follows, with reference to the accompanying drawings.